Subject: Re: [PATCH 22/28] sgiseeq: convert from dma_cache_sync to dma_sync_single_for_device

From: Thomas Bogendoerfer <[email-masked]>
Date: Tue, 1 Sep 2020 17:22:09 +0200

On Wed, Aug 19, 2020 at 08:55:49AM +0200, Christoph Hellwig wrote:
> Use the proper modern API to transfer cache ownership for incoherent DMA.
> 
> Signed-off-by: Christoph Hellwig <[email-masked]>
> ---
>  drivers/net/ethernet/seeq/sgiseeq.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c
> index 39599bbb5d45b6..f91dae16d69a19 100644
> --- a/drivers/net/ethernet/seeq/sgiseeq.c
> +++ b/drivers/net/ethernet/seeq/sgiseeq.c
> @@ -112,14 +112,18 @@ struct sgiseeq_private {
>  
>  static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr)
>  {
> -	dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
> -		       DMA_FROM_DEVICE);
> +	struct sgiseeq_private *sp = netdev_priv(dev);
> +
> +	dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr),
> +			sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL);
>  }
>  
>  static inline void dma_sync_desc_dev(struct net_device *dev, void *addr)
>  {
> -	dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
> -		       DMA_TO_DEVICE);
> +	struct sgiseeq_private *sp = netdev_priv(dev);
> +
> +	dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr),
> +			sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL);
>  }

this breaks ethernet on IP22 completely, but I haven't figured out why, yet.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]